Instant Notes: Analytical Chemistry

possible. Readily extractable solutes, therefore, include covalent neutral mole- cules with few polar and no ionized substituent ...

The efficiencyof an extraction depends on the value of the distribution ratio, D. For solvent extraction, it also depends on the ...

two solutes with distribution ratios D 1 and D 2 , a separationor selectivity factor, b, is defined as b= D 1 /D 2 where D 1 > ...

D (11) and substituting KDfor [HA]ether/[HA]aqfrom equation (9) gives D (12) Equation (12) shows that at low pH, when the acid ...

1-(2-pyridylazo)-2-naphthol (PAN) sodium diethyldithiocarbamate (NaDDTC) (see also Table 1); ∑ Electrically neutral ion-associat ...

should be bulky organic hydrophobic groups to provide high solubility in nonpolar solvents. The metal ion can be a cationic or a ...

waters and soils, polycyclic aromatic hydrocarbons (PAHs) in drinking water, polluted industrial and urban atmospheres, and drug ...

SPE can be semi- or fully-automated to increase sample throughput and to improve both precision and accuracy. The degree of auto ...

very small volumes of sample and solvents rapidly, and having the advan- tage of allowing flow in both directions if required. ● ...

Section D – Separation techniques D2 PRINCIPLES OF CHROMATOGRAPHY Chromatography was originally developed by the Russian botanis ...

separation involves the placing of a sample onto a liquid or solid stationary phaseand passing a liquid or gaseous mobile phaset ...

modes that enable mixtures of either anionic or cationic solutes to be separated. Size-exclusion (SEC) and chiral chromatography ...

VRVM 1 D  (4) or VRVMDVs (5) where Dhas been substituted for kusing the relation kD (6) and the volumes of the stationa ...

mobile phases for TLCand HPLCare to be found listed in Table 1, Topic D6. The more polar the solute, the more tenaciously it wil ...

mobile counter-ions. Both cationicand anionicion-exchangers are available, the exchange processes being represented by the follo ...

● variations in the distribution ratio of a solute with its total concentration also leads to asymmetricalor skewedpeaks (vide i ...

Peak asymmetry The concentration profile of a migrating solute is fundamentally symmetrical (Gaussian), only if the solute distr ...

N5.54 2 (10) Some laboratories favor the use of eqn. (9), but some favour eqn. (10) on the grounds that peak width at half he ...

Example. A gas chromatographic method for the separation of a mixture of cyclohexane, t-butanol and benzene on a 10 m capillary ...

t-butanol/benzene RS = 30/20 = 1.5 Note that (i) The plate numbers are slightly higher when half-height peak widths are used to ...